javascript - 字体不显示在画布上

Question

我在javascript中使用impactjs引擎来绘制字体，我有一个字体图像，并试图在我的画布上绘制它，但是字体没有显示在画布上，我哪里出错了？任何帮助thanx

.defines(function(){

EntityTutorial = ig.Entity.extend({
yellowFont : new ig.Font('/tutorial/yellow.png'),

 draw: function(){
    this.parent();
    console.log("draw");
    this.yellowFont.draw('Swipe from the hero to the Blue Team Soldier to release a Lightning Dragon',ig.game.screen.x+100,100,ig.Font.ALIGN.RIGHT);
    //this.blueFont.draw('dfdfd',ig.game.screen.x+100,100,ig.Font.ALIGN.RIGHT);
}
});